Electromagnetic Spectrum

1
Electromagnetic Spectrum

• An Overview

2
(No Transcript)
3
(No Transcript)
4
What is it??

• The electromagnetic spectrum is a table / chart
  that shows all of the different waves of light
  that exist.
• All of the light waves listed on the
  electromagnetic spectrum travel at the same
  speed which is 300,000,000 m/s.
• Examples of waves include radio waves,
  microwaves, visible light.

5
Radio Waves

• Radio waves have some of the longest wavelengths
  and lowest frequencies therefore they are low
  energy waves

• Radio stations encode sound waves by adjusting
  amplitude / frequency.
• AM Amplitude Modulation
• FM Frequency Modulation

6
AM vs. FM

• AM waves can travel farther than FM waves.
• Most radio stations will use FM because they can
  encode more information in the wave.

7
Television

• TV is also carried by radio waves. TV uses FM to
  carry sound and AM to carry picture.

• Cable works by transmitting waves to satellite
  dishes. These waves are amplified and then
  relayed back to the antennae and finally the TV.

8
Microwaves

• Microwaves have shorter wavelengths and higher
  frequencies than radio waves.
• They carry more energy than radio waves.
• A microwave works when a magnetron produces
  microwaves. Next, these waves bounce off of a
  metal fan and then penetrate the food. These
  waves make the water molecules in the food
  vibrate and become hot.

9
Microwaves and radar

• A radar gun or radar in general uses microwaves
  to perform its most basic function.

• When a police man clocks how fast a car is going
  it shoots microwaves at the car and then it
  bounces off the car to the radar gun. Then a
  computer can calculate how fast the car is
  traveling.

10
Infrared Waves

• Have shorter wavelengths and higher frequencies
  than microwaves.
• Infrared waves are why you feel warm on a summer
  day.
• The warmer the object the more infrared waves are
  produces. And visa versa.

11
Visible Light

• Very narrow range of wavelengths and frequencies.
  
• The longest wavelengths are seen as red light and
  the shortest are seen as violet light.
• Because violet light carries the shortest
  wavelength it has the most energy.
• The colors of light is a culmination of the 7
  colors roygbiv

12
Ultraviolet Light

• Type of wave produced by the sun.
• Have shorter wavelengths and higher frequencies
  than visible light.

• They have both positive and negative effects.
• Positive kills bacteria on food
• Negative can harm skin cells and cause cancer.

13
X Rays

• Very short wavelength and high frequencies. X
  rays carry a great deal of energy and can
  penetrate through many surfaces. This application
  makes it useful in a medical field. However to
  many x-rays can kill living cells and be toxic.
  Patients that receive x-rays will usually wear a
  led apron to protect the other parts of the body
  not being examined.

14
Gamma Rays

• Gamma rays carry large amounts of energy and can
  penetrate objects easily. Some doctors will use
  gamma rays to radiate and kill cancer cells. This
  method has both positives and negatives.
  Positive it kills the cancer cells. Negative It
  also kills some of the healthy cells in the body.